March 23 (Reuters) - Sanofi's (SASY.PA) asthma drug Dupixent met all targets in a trial to treat "smoker's lung", potentially adding billions to the French drugmaker's growth prospects, but also underscoring a heavy reliance on its bestseller.

In a late stage trial Dupixent, jointly developed with Regeneron (REGN.O), led to a 30% reduction in moderate or severe acute exacerbations of chronic obstructive pulmonary disease (COPD), a potentially deadly disease marked by progressive lung function decline.

Shares in Sanofi and Regeneron surged after they said in a joint statement on Thursday a Phase III trial involving 939 current or former smokers also showed improvements in lung function, quality of life and respiratory symptoms.

The French group's stock was up 5.2% at 1205 GMT, reaching a seven-month high and far outperforming the STOXX Europe 600 Health Care index (.SXDP), which was little changed.

Regeneron jumped 8.6% in U.S. premarket trade and was set to open at a record high.

"COPD is an urgent global health concern and a notoriously difficult-to-treat disease due to its heterogeneity, with no novel treatments approved in more than a decade," said Regeneron Chief Scientific Officer George Yancopoulos.

Sanofi added its "bold" decision to go without earlier-stage clinical COPD trials had shaved years off the development time.

JP Morgan analyst Richard Vosser said the trial update had "blow-out data" in store for investors, and that market consensus for 2027 Dupixent sales of 15.7 billion euros would likely be topped-up by between 1 and 2 billion euros.

"We see Dupixent data in COPD exceeding any expectations in the market for benefit," the analyst said.

Jefferies analysts said the update yielded "perhaps best case efficacy" to treat the disease.

Sanofi previously forecast Dupixent would generate up to 13 billion euros ($14.2 billion) in sales in its best year as it seeks to widen its use across several inflammatory conditions, but it has excluded COPD from its sales target.

Sanofi said on Thursday it was too early to update its sales estimate for the product, which is also used to ease eczema.

The anti-inflammatory drug accounted for 8.3 billion euros, or more than 19% of the French group's overall sales of 43 billion euros, last year. That was a currency-adjusted increase of 44% from a year earlier.

Sanofi reports combined global Dupixent sales from its alliance with Regeneron.

The companies said that full efficacy and safety results would be presented later. They added a second late-stage COPD Dupixent trial was ongoing, with the first data read-out expected next year.

Overall rates of adverse events in the trial reporting results were 77% for Dupixent and 76% for placebo.

Sanofi shares have been battered following disappointing trial results in August 2022 of a once-promising breast cancer drug candidate.

Legal claims that heartburn drug Zantac caused cancer have also weighed on the stock.

The group, led by British CEO Paul Hudson, this month struck a deal to acquire Provention Bio Inc (PRVB.O) for $2.9 billion to bolster its work on a U.S.-approved type 1 diabetes therapy.

Analysts have said that this year's expected market debut of two new products, to balance out reliance on Dupixent, would be important tests of the company's marketing and development prowess and a chance to regain investor confidence.

These products are haemophilia A treatment Altuviiio, requiring fewer injections than standard therapy, and Beyfortus from a partnership with AstraZeneca (AZN.L), which is a preventive injection against the common RSV airways infection in infants.

Sanofi and Regeneron on Tuesday announced the European Commission had approved Dupixent to treat severe atopic dermatitis in young children. Prior to that, the drug was also approved in Europe to treat a type of esophagus inflammation.

Reference：

https://www.reuters.com/business/healthcare-pharmaceuticals/sanofi-regenerons-dupixent-meets-endpoints-clinical-trial-2023-03-23/